Starting mechanisms for internal combustion engines

ABSTRACT

In combination with an internal combustion engine, an electric starter motor is mounted with the axis of the starter motor substantially radial to the crankshaft of the engine and having the slidable pinion of the starter motor counter-balanced to resist gravity induced movement of the pinion in a direction to mesh with the gear mounted on the crankshaft.

United- States Patent [191 Chamberlain STARTING MECHANISMS FOR INTERNAL COMBUSTION ENGINES I [76] Inventor:

St., Port Melbourne, Australia [22] Filed: Oct. 6, 1972 [21] Appl. No.: 295,783

[30] Foreign Application Priority Data Oct. 7, I97] Australia 6557/7! 52 UiS.'Cl. 74/8 [51] Int. Cl. F02n 15/02 [58] Field of Search 74/8 [56] References Cited UNITED STATES PATENTS 2,823,546 2/1958 Barrett 74/8 Alan Hawker Chamberlain, 95 Dow I [4 1 Mar. 12, 1974 Primary ExaminerAllan D. l-lerrmann Attorney, Agent, or Firm-George Vande Sande 5 7 ABSTRACT lncombination with an internal combustion engine, an electric starter motor is mounted with the axis of the starter motor substantially radial to the crankshaft of the engine and having the slidable pinion of the starter motor counter-balanced to resist gravity induced movement of the pinion in a direction to mesh with the gear mounted on the crankshaft.

3 Claims, 2 Drawing Figures STARTING MECHANISMS FOR INTERNAL COMBUSTION ENGINES This invention relates to a starting mechanism for an internal combustion engine of the general type wherein an electric starter motor may be selectively engaged with a gear connected to the engine crankshaft to rotate the latter for the purpose of starting the engine.

It is common practice to use internal combustion engines designed and built for use in road vehicles, as the engine for a boat, particularly in high speed pleasure boats. In the current design of engines for road vehicles, the starter motor is normally disposed with its axis parallel to the axis of the crank-shaft, and includes a pinion which may mesh with a ring gear mounted on theperiphery of the engine flywheel. The starter motor is normally mounted on the lower portion of the engine block, and in the current V8 type of engine, the axis of the starter motor is commonly below the axis of the crankshaft.

When these engines are installed in boats, the low disposition of the starter motor on the cylinder block, results in the starter motor being located in the bilge of the boat. In this position, the starter motor is, of course, exposed to the possibility of water entering the starter motor with resultant short-circuiting of the electrical system. In addition, combustible gases arising from fuel leakage commonly accumulate in the bilge, and the sparking of the starter motor commutator during normal operation presents a high fire risk.

It is the object of the present invention to provide a starter motor mechanism which may readily be adapted for fitment to conventional internal combustion engines, but will locate the starter motor at a relatively high position where the risk of damage by water or the igniting of combustion gases is substantially reduced.

With this object in view, there is provided by the present invention in combination an internal combustion engine having a crankshaft and a gear mounted coaxially on the crankshaft, an electric starter motor having a shaft pinion drive coupled to and axially slidable on the motor shaft, means mounting the starter motor on the engine so that the pinion will engage the gear in response to axial movement of the pinion in one direction, the mounting means being arranged so that the starter motor is disposed above the axis of the crankshaft with the motor shaft disposed substantially radial thereto, means to selectively axially move the pinion into and out of engagement with the gear, and counterbalanced to resist gravity induced axial movement of the pinion in the direction to engage the gear.

Preferably, the starter motor is located so that the axis of the motor shaft is in the vertical plane passing through the axis of the engine crankshaft.

In boats, the forces to which'components are subjected as a result of the vertical movement of the boat while under way, are quite substantial and can vary from 4 gs in the stern of a boat to as high as 16 gs in the bow when the boat is operating under high speed racing conditions. These forces are sufficient to cause the movable pinion of the starter motor to move along the starter motor shaft when the starter motor is mounted with the shaft axis in a substantially vertical plane. This, of course, may cause the pinion to engage the gear on the flywheel while the motor is running with resultant severe damage to the respective components. However, by counter-balancing the pinion, the g forces experienced do not tend to move the pinion into engagement.

The invention will be more readily understood from the following description of one practical arrangement of the starter motor and the mounting thereof on an engine, as illustrated in the accompanying drwings.

In the drawings, FIG. 1 is a view of the engine with the starter motor mounted thereon; and

FIG. 2 is an enlarged view of the starter motor partly in section.

Referring now to the drawings, the starter motor 5 is mounted by bolts 4 on the housing 6 attached to the block of the engine 7 and surrounding the fly wheel 8 carrying the gear 9, the axis of the starter motor shaft 10 being in a vertical plane with the lower end of the shaft projecting into the housing 6.

The starter motor 5 is generally of the conventional construction having the pinion 12 mounted on the motor shaft 10 for sliding movement thereon and is driven by the shaft in the usual manner. The thrust fork 14 is pivotally supported on the pin 13 for angular movement about an axis transverse to the axis of the motor shaft. The bifurcated end 15 of the fork engages the recess 16 in the pinion thrust bearing 17, and the other end of the fork is connected to the extension 19 of the armature of the solenoid 20. Upon energizing the solenoid, the thrust fork is pivoted on the pin 13 to axially slide the pinion 12 downwardly to engage the gear 9 on the flywheel since the pinion 12 is connected to bearing 17 through sleeve 18.

The pivot axis of the thrust fork is located intermediate the ends thereof, and the weight and disposition of the centre of gravity of the portion of the thrust fork on the opposite side of the axis to the pinion, is selected so as to counter-balance the weight of the pinion 12, the thrust bearing 17 and the portion of the thrust fork on the pinion side of the pivot axis. This weight distribution is conveniently achieved by attaching the counter-weight 21 to the fork 14 on the side opposite the pinion.

As a result of this counter-balance, any inertia forces acting on the pinion and thrust bearing as a result of vertical movement of the engine are balanced by the inertia forces acting on the other end of the thrust fork, and thus there is no resultant force tending to move the pinion 12 into engagement with the gear 9. I

As the axis of the starter motor is now disposed radially with respect to the crankshaft of the engine, the teeth of the gear 9 on the flywheel must also be disposed substantially radially to the crankshaft as compared with the parallel disposition of the teeth in the conventional engine. Furthermore, the radial disposition of the starter motor permits the motor to be positioned above the plane of the crankshaft as the engine block, cylinder head or other parts of the engine do not obstruct the starter motor, as occurs when the axis of the starter motor is parallel to the crankshaft.

I claim:

1. In combination an internal combustion engine having a crankshaft and a gear mounted coaxially on the crankshaft, an electric starter motor having a shaft and a pinion drive coupled to and axially slidable on the motor shaft, means mounting the starter motor on the engine so that the pinion will engage the gear in response to axial movement of the pinion in one direction, the mounting means being arranged so that the starter motor is disposed above the axis of the crankmeans to move the pinion comprise a link pivoted intermediate its length and operatively connected to the pinion and a solenoid so that the link moves the pinion into mesh with the gear when the solenoid is energised, the link including a counter weight disposed to pivot the link in a direction to disengage the pinion from the gear when the solenoid is not energized. 

1. In combination an internal combustion engine having a crankshaft and a gear mounted coaxially on the crankshaft, an electric starter motor having a shaft and a pinion drive coupled to and axially slidable on the motor shaft, means mounting the starter motor on the engine so that the pinion will engage the gear in response to axial movement of the pinion in one direction, the mounting means being arranged so that the starter motor is disposed above the axis of the crankshaft with the motor shaft disposed substantially radial thereto, means to selectively axially move the pinion into and out of engagement with the gear, and counter-balanced to resist gravity induced axial movement of the pinion in the direction to engage the gear.
 2. The combination as claimed in claim 1 wherein the starter motor is disposed with the axis of the shaft threof in a plane substantially vertical.
 3. The combination as claimed in claim 1 wherein the means to move the pinion comprise a link pivoted intermediate its length and operatively connected to the pinion and a solenoid so that the link moves the pinion into mesh with the gear when the solenoid is energised, the link including a counter weight disposed to pivot the link in a direction to disengage the pinion from the gear when the solenoid is not energized. 